This invention relates to the field drill bit sharpening. More specifically, this invention relates to the field of sharpening fine drill bits frequently used for drilling holes in printed circuit boards. Even more specifically, this invention relates to the procedure for properly positioning the drill bit to be sharpened before sharpening it.
The inspiration of this invention centers on the need to reuse dulled drill bits used for drilling holes in circuit boards. Circuit boards are sensitive materials that require special types of drill bits that are quite costly. The drill bits are used in extensive quantity and dull often. Once the drill bits begin to dull, they will regularly damage circuit boards if not replaced. Thus it has become more cost effective to resharpen drill bits and reuse them, than discarding dulled drill bits.
Sharpening a drill bit in this field means sharpening the drill bit tip, as the web of the drill bit rarely suffers enough wear to require sharpening. The most difficult task in sharpening the drill bit tip is ascertaining where along the drill bit tip the edge is supposed to be located. Once the location for the sharpening is properly located, applying the drill bit to the necessary grinding devices becomes a simple process. Failure to ascertain the correct location can result in improper grinding and sharpening that will require discarding or resharpening the drill bit. As every drill bit can only be sharpened a finite number of times before being worn down too far to be resharpened and reused, an improperly sharpened drill bit is a costly problem.
One method of ascertaining the location for the drill bit tip edge is simply using the human eye. The drill bit is held within a rotating arm of a machine and operators of the machine peer at the drill bit tip through a microscope, which normally has cross hairs on the lens. The machine operators can then rotate the arm of the machine by fractions of degrees to rotate the drill bit until the edge of the used drill bit lines up with the cross hairs.
This method has several flaws. The greatest flaw is using the drill bit tip to determine where the drill bit tip edge should be. After the number of times the drill bit has been used, the drill bit tip is dulled and flawed. It would seem obvious that using a flawed piece of the structure to correct the structure""s flaw is an imperfect procedure. Depending on the condition of the tip, the individual sharpening the tip is required to use a degree of judgment in determining where the tip belongs in relation to its altered state. As a result, the sharpening is a very imperfect science resulting in improperly sharpened drill bits.
Another problem with this method is its dependency on human judgment. Human operators, without any scientific backing, are left to judge where along the drill bit tip the sharpened edge belongs. Using a flawed tip and the cross-hairs in the microscope, the operators must choose the location to sharpen on a trial and error basis. This guessing method causes inconsistent results.
Another problem with this method is it is often difficult to determine whether the drill bits were improperly sharpened. The manufacturer using the drill bits doesn""t have the time to examine each drill bit under a microscope to determine if the sharpened edge on the drill bit tip is flawed. While sometimes flawed sharpened drill bits will result in obvious damage to the circuit boards, other times the flawed sharpened drill bits will result in non-obvious damage to the circuit boards that is only discovered after the eventual circuit board users discover the circuit boards are dysfunctional. Therefore the unpredictable results that come with human operators using a flawed system are a serious problem.
Another method for finding the edge to sharpen drill bits is using a digital imaging device to view the drill bit in the same manner the human operator was viewing the drill bit in the other method. The digital imaging device finds the location of the drill bit tip and allows the operator to position the drill bit for sharpening much more smoothly. However this method also contains the same flaws as the previous method. This method depends on a flawed piece of the drill bit structure to correct the structure flaw. This method requires trial and error judgment based on the condition of the drill bit to sharpen it. This method produces drill bits with flawed tips inconsistently.
This invention results from the realization that a drill bit can be positioned for sharpening without using the flawed tip as a reference point allowing the drill bit to be sharpened with an insignificant level of human judgment and with consistently less flawed results.
It is therefore an object of this invention that the drill bits get positioned for sharpening without regard to the condition of the drill bit tip.
It is therefore a further object of this invention that the drill bits get positioned for sharpening without depending on separate human judgment for each drill bit.
It is therefore a further object of this invention that the drill bits get positioned for sharpening based on consistent calculations referencing the geometric shape of the drill bits.